Fluid Dynamic Vent Dam

ABSTRACT

The disclosure provides in one embodiment for a vent dam for use in a vent stringer in a fuel vent system. The vent dam is configured to mount to and within the vent stringer The vent dam has a contoured guiding surface for guiding fuel flow into and out of an interior of the vent stringer, wherein the vent dam, the vent stringer, and a tube attached to the vent stringer are in fluid communication with one or more fuel tanks. The vent dam further has one or more side flanges extending from the contoured guiding surface for providing attachment of the vent dam to one or more interior portions of the vent stringer, wherein the contoured guiding surface and the one or more side flanges are formed as one piece.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a divisional of and claims priority topending application Ser. No. 12/652,020, filed Jan. 4, 2010, entitled“Fluid Dynamic Vent Dam”, the entire contents of which is incorporatedherein by reference, and which is related to U.S. application Ser. No.12/638,976, entitled “High PullOff Capability Hat Stringer”, filed onDec. 15, 2009, and abandoned on Sep. 17, 2010, the entirety of which isincorporated by reference herein, and which is also related to U.S.application Ser. No. 12/474,005, entitled “Stringer Transition Method”,filed on May 28, 2009, and issued as U.S. Pat. No. 8,074,694 on Dec. 13,2011, the entirety of which is incorporated by reference herein, andwhich is also related to U.S. application Ser. No. 12/332,093, entitled“Method for Producing Composite Laminates Using a Collapsible Mandrel”,filed on Dec. 10, 2008, and issued as U.S. Pat. No. 8,293,051 on Oct.23, 2012, the entirety of which is incorporated

BACKGROUND

1) Field of the Disclosure

The disclosure relates generally to fuel vent systems in aircraft andother craft, and more particularly, to a vent dam configuration andmethod for use in a structural fuel vent stringer system in an aircraft.

2) Description of Related Art

Composite structures are used in a wide variety of applications. Inaircraft construction, composites are used in increasing quantities toform the fuselage, wings, tail section, and other components. Forexample, the wings may be constructed of composite skin members to whichstiffening elements, such as stringers, may be coupled to increase thebending strength and stiffness of the skin member. The stringers mayextend in a generally span wise direction along the wing. The stringersmay be bonded to the skin members and may be configured to carry bendingloads or loads that are oriented substantially perpendicularly relativeto the skin member.

Stringers may be provided in a wide variety of cross-sectional shapes.For example, a stringer cross-section may comprise a plurality ofcomposite plies formed in a hat section configuration having a baseportion and a pair of webs extending outwardly from the base portion.The base portion may comprise a pair of flanges to facilitate coupling(e.g., bonding) of the stringer to the skin member, such as the upperand lower wing skins of a wing. The hat section stringer may include acap which interconnects the webs and encloses the hat section in orderto increase the torsional rigidity of the stringer.

The stringers in a wing may extend from an inboard section of the wingto an outboard section of the wing. The stringers may include purelystructural non-vent stringers and stringers that serve both asstructural and system elements, such as vent stringers. Both types ofstringers provide a primary load carrying function. The vent stringersmay provide a secondary function by acting as a conduit for venting fueland fuel vapors from the inboard sections of the wing fuel tanks tosurge tanks. The vent stringers may include several vent dams that serveas fuel tank boundaries or barriers to ensure that the fuel and fuelvapor flow travels in the desired direction. Known vent dams exist. Suchknown vent dams may be made of sheet metal and have a flat plate surfaceattached at 90 degree angles to four side wall flanges. Because suchknown vent dams only act to block fuel flow, the fuel flow can impingeon an upper wing skin when entering the vent stringer and then mustchange direction by 90 degrees to flow down a vent stringer channel.Moreover, when the fuel flow enters the vent stringer, the fuel flow canimpinge on the vent dam. Such fuel flow impingement on the upper wingskin and the vent dam, as well as an instantaneous 90 degree change offlow direction can result in turbulence and pressure drop or loss. Suchpressure drop or loss can result in higher structural loads and adecreased refuel rate.

Accordingly, there is a need in the art for an improved vent damconfiguration and method for use in a vent stringer system that providesadvantages over known vent dam configurations and methods.

SUMMARY

This need for an improved vent dam configuration and method for use in avent stringer system is satisfied. Unlike known vent dams, embodimentsof the vent dam configuration and method may provide numerousadvantages. The vent dam configuration and method provides an improvedvent dam and method where the vent dam has a guiding surface that may becurved or sloped for efficiently and smoothly directing and improvingfluid flow, such as fuel flow and vapor flow, in a vent stringer system.The vent dam configuration and method provides an improved vent dam andmethod that prevents or minimizes turbulence in a fluid flow, such asfuel flow and vapor flow, in a vent stringer, thus, reducing pressuredrop or loss and resulting in an increased refuel rate. The vent damconfiguration and method provides a vent dam and method where the ventdam is located relative to a vent stringer access opening and relativeto a fluid flow, such as a fuel flow or vapor flow, so as to optimizethe fluid flow into and out of the vent stringer. The vent damconfiguration and method provides an improved vent dam and method wherethe vent dam may be comprised of one piece or multiple pieces to enableeasy access of the vent dam through the vent stringer access opening, toeliminate the need for blind fasteners, and to allow for effectivesealant application, thus resulting in efficient installation,fastening, and sealing of the vent dam within the vent stringer.

In an embodiment of the disclosure, there is provided a vent dam for usein a vent stringer in a fuel vent system. The vent dam is configured tomount to and within the vent stringer. The vent dam comprises acontoured guiding surface for guiding fuel flow into and out of aninterior of the vent stringer, wherein the vent dam, the vent stringer,and a tube attached to the vent stringer are in fluid communication withone or more fuel tanks. The vent dam further has one or more sideflanges extending from the contoured guiding surface for providingattachment of the vent dam to one or more interior portions of the ventstringer, wherein the contoured guiding surface and the one or more sideflanges are formed as one piece.

In another embodiment of the disclosure there is provided an aircraftstructure. The aircraft structure comprises at least one wing and atleast one vent stringer mounted to the at least one wing. The at leastone vent stringer comprises a base portion, first and second web wallsextending outwardly from the base portion, a cap portion, and an accessopening in the cap portion. The access opening is configured forinsertion and installation of vent dams. The aircraft structure furthercomprises at least one fuel tank

The vent dams are mounted to and within the at least one vent stringer.The vent dams each comprise a contoured guiding surface for guiding fuelflow into and out of an interior of the at least one vent stringer,wherein the vent dams, the at least one vent stringer, and a tubeattached to the at least one vent stringer are in fluid communicationwith the at least one fuel tank The vent dams each further comprise oneor more side flanges extending from the contoured guiding surface forproviding attachment of the vent dams to one or more interior portionsof the at least one vent stringer, wherein at least one of the vent damsis formed as one piece.

In another embodiment of the disclosure there is provided a method forproviding improved fluid flow in a vent stringer of a fuel vent system.The method comprises attaching one or more side flanges of a vent dam toone or more interior portions of the vent stringer in a fuel tank, thevent dam being adjacent to an opening in the vent stringer. The vent damincludes a contoured guiding surface and the one or more side flangesextending from the contoured guiding surface, and the contoured guidingsurface and the one or more side flanges are formed as one piece.

The method may further comprise introducing a fluid flow through theopening in the vent stringer. The method may further comprise using thecontoured guiding surface to guide the fluid flow into and out of thevent stringer, wherein the vent dam, the vent stringer, and a tubeattached to the vent stringer are in fluid communication with the fueltank The method may further comprise using the contoured guiding surfaceto prevent turbulence in the fluid flow which results in a reducedpressure drop across the vent dam to improve fluid flow in the ventstringer of the fuel vent system.

The attaching the one or more side flanges of the vent dam may compriseattaching the vent dam with the contoured guiding surface being curvedand having a bend radius. The attaching the one or more side flanges ofthe vent dam may comprise inserting one or more fastener elementsthrough one or more flange holes defined through an end flange of thevent dam to fasten and secure the end flange of the vent dam to the ventstringer in the fuel tank The attaching the one or more side flanges ofthe vent dam may comprise mechanically attaching the one or more sideflanges to the vent stringer via one or more fastener elements. Theattaching the one or more side flanges of the vent dam may comprisebonding the one or more side flanges to the vent stringer via a bondingagent.

In another embodiment of the disclosure there is provided a vent dam foruse in a vent stringer in a fuel vent system. The vent dam comprises acontoured guiding surface for guiding fluid flow in a vent stringer. Thevent dam further comprises one or more side flanges extending from thecontoured guiding surface for providing attachment of the vent dam tothe vent stringer.

In another embodiment of the disclosure, there is provided a fluiddynamic fuel vent dam for use in a vent stringer in a fuel tank The ventdam comprises a first piece joined to a second piece with an overlappingconfiguration at a seam formed between the first piece and the secondpiece. The vent dam further comprises a curved guiding surface forguiding fuel flow in a vent stringer. The vent dam further comprises oneor more side flanges extending from the curved guiding surface forproviding attachment of the vent dam to one or more interior portions ofthe vent stringer.

In another embodiment of the disclosure, there is provided an aircraftstructure. The aircraft structure comprises at least one wing and atleast one vent stringer mounted to the wing. The vent stringer comprisesa base portion, first and second web walls extending outwardly from thebase portion, a cap portion, and an opening. The aircraft structurefurther comprises at least one fuel tank The aircraft structure furthercomprises at least one vent dam mounted within the vent stringer. Thevent dam comprises a contoured guiding surface for guiding fluid flowinto and out of the vent stringer. The vent dam further comprises one ormore side flanges extending from the contoured guiding surface forproviding attachment of the vent dam to the vent stringer.

In another embodiment of the disclosure, there is provided a method forproviding improved fluid flow in a vent stringer of a fuel vent system.The method comprises providing a vent dam comprising a contoured guidingsurface and one or more side flanges extending from the contouredguiding surface. The method further comprises installing the vent dam ina vent stringer adjacent to an opening in the vent stringer. The methodfurther comprises introducing a fluid flow through the opening in thevent stringer. The method further comprises using the contoured guidingsurface to guide the fluid flow into and out of the vent stringer. Themethod further comprises using the contoured guiding surface to preventturbulence in the fluid flow which results in a reduced pressure dropacross the vent dam to improve fluid flow in the vent stringer of thefuel vent system.

In another embodiment of the disclosure, there is provided a method forproviding improved fuel flow in a vent stringer in a fuel tank Themethod comprises providing a vent dam comprising a first piece joined toa second piece with an overlapping configuration at a seam formedbetween the first piece and the second piece, the vent dam furthercomprising a contoured guiding surface and one or more side flangesextending from the contoured guiding surface. The method furthercomprises attaching the one or more side flanges of the vent dam to oneor more interior portions of the vent stringer in the fuel tank, thevent dam being adjacent to an opening in the vent stringer. The methodfurther comprises introducing a fuel flow through the opening in thevent stringer. The method further comprises using the contoured guidingsurface to guide the fuel flow into and out of the vent stringer. Themethod further comprises using the contoured guiding surface to preventturbulence in the fuel flow which results in a reduced pressure dropacross the vent dam to improve fuel flow in the vent stringer in thefuel tank

The features, functions, and advantages that have been discussed can beachieved independently in various embodiments of the disclosure or maybe combined in yet other embodiments further details of which can beseen with reference to the following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure can be better understood with reference to the followingdetailed description taken in conjunction with the accompanying drawingswhich illustrate preferred and exemplary embodiments, but which are notnecessarily drawn to scale, wherein:

FIG. 1 is an illustration of a perspective view of an aircraft which mayincorporate one or more advantageous embodiments of the vent dam of thedisclosure;

FIG. 2 is an illustration of a flow diagram of an aircraft productionand service methodology;

FIG. 3 is an illustration of a functional block diagram of an aircraft;

FIG. 4 is an illustration of a functional block diagram of an aircraftstructure of a wing with a vent stringer having an embodiment of a ventdam of the disclosure;

FIG. 5 is an illustration of a top view of a vent stringer system in aleft aircraft wing box showing locations of vent stringers and anembodiment of vent dams of the disclosure;

FIG. 6 is an illustration of a top close-up view of a vent stringersystem of a left wing of an aircraft showing locations of vent stringersand an embodiment of vent dams of the disclosure;

FIG. 7 is an illustration of a top view of vent stringers with anembodiment of vent dams of the disclosure;

FIG. 8 is an illustration of a close-up view of circled portion 8 ofFIG. 7 showing a top view of an embodiment of a vent dam of thedisclosure used as a fuel tank boundary;

FIG. 9 is an illustration of a close-up view of circled portion 9 ofFIG. 7 showing fluid flow through a left main tank climb port;

FIG. 10 is an illustration of a close-up view of circled portion 10 ofFIG. 9 showing a perspective view of an embodiment of a vent dam of thedisclosure used to guide fluid flow into a vent stringer;

FIG. 11 is an illustration of a cross-sectional view of an embodiment ofa vent dam of the disclosure having a sloped guiding surface;

FIG. 12 is an illustration of a cross-sectional view of an embodiment ofa vent dam of the disclosure having a sloped guiding surface;

FIGS. 13A-13D are illustrations of views of an embodiment of a vent damof the disclosure;

FIG. 13E is an illustration of a front perspective view of the vent damof FIG. 13A installed in a vent stringer;

FIG. 13F is an illustration of a cross-sectional view of the vent damtaken along line 13F-13F of FIG. 13E showing an embodiment of anattachment element for connecting the pieces of the vent dam;

FIG. 13G is an illustration of a bottom view of the vent stringer withthe vent dam of FIG. 13A installed in the vent stringer;

FIG. 13H is an illustration of a cross-sectional view of the vent damtaken along line 13H-13H of FIG. 13G showing an embodiment of a fastenerelement for connecting the vent dam to the vent stringer;

FIGS. 14A-14D are illustrations of views of another embodiment of a ventdam of the disclosure;

FIG. 14E is an illustration of a front perspective view of the vent damof FIG. 14A installed in a vent stringer;

FIG. 14F is an illustration of a bottom perspective view of the vent damof FIG. 14A installed in the vent stringer;

FIG. 14G is an illustration of a perspective view of the vent dam ofFIG. 14A without any flange holes;

FIG. 15 is an illustration of a cut-away side view of the vent daminstalled in a vent stringer and showing fuel flow;

FIGS. 16A-16D are illustrations of views of another embodiment of a ventdam of the disclosure;

FIG. 16E is an illustration of a cut-away front view of the vent dam ofFIG. 16A installed in a vent stringer;

FIG. 16F is an illustration of a bottom perspective view of the vent damof FIG. 16A installed in a vent stringer;

FIG. 16G is an illustration of a bottom view of the vent dam of FIG. 16Ainstalled in a vent stringer;

FIG. 16H is an illustration of a top view of the vent dam of FIG. 16Ainstalled in a vent stringer;

FIG. 16I is an illustration of a perspective view of the vent dam ofFIG. 16A without any flange holes;

FIG. 17 is an illustration of a cut-away side view of the vent dam ofFIG. 16A installed in a vent stringer and showing fluid flow;

FIGS. 18A-18D are illustrations of views of another embodiment of a ventdam of the disclosure;

FIGS. 19A-19C are illustrations of views of another embodiment of a ventdam of the disclosure;

FIGS. 20A-20C are illustrations of views of another embodiment of a ventdam of the disclosure;

FIGS. 21A-21D are illustrations of views of another embodiment of a ventdam of the disclosure;

FIG. 21E is an illustration of a perspective view of the vent dam ofFIG. 21A without any flange holes;

FIG. 22 is an illustration of a front perspective view of an embodimentof a vent dam of the disclosure installed in a vent stringer withsealant material;

FIG. 23 is an illustration of a bottom view of the vent dam of FIG. 22showing the vent dam installed in the vent stringer with sealantmaterial;

FIG. 24 is an illustration of a flow diagram of an embodiment of amethod of the disclosure for providing improved fluid flow in a ventstringer system; and,

FIG. 25 is an illustration of a flow diagram of another embodiment of amethod of the disclosure for providing improved fuel flow in an aircraftusing vent stringers for fuel tank venting.

DETAILED DESCRIPTION

Disclosed embodiments will now be described more fully hereinafter withreference to the accompanying drawings, in which some, but not all ofthe disclosed embodiments are shown. Indeed, several differentembodiments may be provided and should not be construed as limited tothe embodiments set forth herein. Rather, these embodiments are providedso that this disclosure will be thorough and will fully convey the scopeof the disclosure to those skilled in the art.

FIG. 1 is an illustration of a perspective view of an aircraft 10 whichmay incorporate one or more advantageous embodiments of a vent dam 20 ofthe disclosure. The aircraft 10 may be made from composite and/ormetallic parts that may be used on portions of the aircraft 10,including but not limited to, wings 12, a fuselage 14, a tail 16, and anose 18. One or more vent dams 20 may be positioned on one or both wings12. Although the vent dam 20 is shown in an exemplary embodiment as usedin an aircraft, the vent dam 20 may also be used in other structureswhere a structural element may be used as a fuel venting conduit or aventing conduit.

FIG. 2 is a flow diagram of an aircraft production and servicemethodology 200. FIG. 3 is a functional block diagram of an aircraft202. Referring to FIGS. 2-3, embodiments of the disclosure may bedescribed in the context of the aircraft manufacturing and servicemethod 200 as shown in FIG. 2 and the aircraft 202 as shown in FIG. 3.During pre-production, exemplary method 200 may include specificationand design 204 of the aircraft 202 and material procurement 206. Duringproduction, component and subassembly manufacturing 208 and systemintegration 210 of the aircraft 202 takes place. Thereafter, theaircraft 202 may go through certification and delivery 212 in order tobe placed in service 214. While in service by a customer, the aircraft202 is scheduled for routine maintenance and service 216 (which may alsoinclude modification, reconfiguration, refurbishment, and so on).

Each of the processes of method 200 may be performed or carried out by asystem integrator, a third party, and/or an operator (e.g., a customer).For the purposes of this description, a system integrator may includewithout limitation any number of aircraft manufacturers and major-systemsubcontractors; a third party may include without limitation any numberof vendors, subcontractors, and suppliers; and an operator may be anairline, leasing company, military entity, service organization, and soon.

As shown in FIG. 3, the aircraft 202 produced by exemplary method 200may include an airframe 218 with a plurality of systems 220 and aninterior 222. Examples of high-level systems 220 include one or more ofa propulsion system 224, an electrical system 226, a hydraulic system228, and an environmental system 230. Any number of other systems may beincluded. Although an aerospace example is shown, the principles of theinvention may be applied to other industries, such as the automotiveindustry.

Apparatus and methods embodied herein may be employed during any one ormore of the stages of the production and service method 200. Forexample, components or subassemblies corresponding to production process208 may be fabricated or manufactured in a manner similar to componentsor subassemblies produced while the aircraft 202 is in service. Also,one or more apparatus embodiments, method embodiments, or a combinationthereof may be utilized during the production stages 208 and 210, forexample, by substantially expediting assembly of or reducing the cost ofan aircraft 202. Similarly, one or more of apparatus embodiments, methodembodiments, or a combination thereof may be utilized while the aircraft202 is in service, for example and without limitation, to maintenanceand service 216.

FIG. 4 is an illustration of a functional block diagram of an aircraftstructure 22. The aircraft structure 22 comprises at least one wing 12having a fuel vent system 52. The aircraft structure 22 furthercomprises one or more fuel tanks 46 with climb ports 24 and tubes 26.The aircraft structure 22 further comprises at least one vent stringer28. The vent stringer 28 comprises a cap portion 30 and an opening 32.The vent stringer 28 further comprises a base portion 34 having a firstflange 36 and a second flange 38. The vent stringer 28 further comprisesa first web wall 40 extending outwardly from the first flange 36 of thebase portion 34. The vent stringer 28 further comprises a second webwall 42 extending outwardly from the second flange 38 of the baseportion 34. The vent stringer 28 may further comprise one or more attachflange fittings 44 which may be attached to the base portion 34 and maybe further attached to the first and second web walls 40, 41. The ventstringer 28 is preferably within the one or more fuel tanks 46 and ispreferably a part of the one or more fuel tanks 46.

The aircraft structure 22 further comprises at least one vent dam 20mounted within the vent stringer 28. Preferably, the vent dam 20 isfluid dynamic to smoothly funnel fluid flow past the vent dam.Preferably, the vent dam 20 may be used in the fuel vent system 52 ofvarious types of aircraft or other craft. The vent dam 20 comprises atleast one contoured guiding surface 48 for guiding fluid flow 74 (seeFIG. 9) into and out of the vent stringer 28. The contoured guidingsurface 48 provides for smooth fluid flow 74 (see FIG. 9) by preventingor minimizing turbulence in the fluid flow which can result in reducedpressure drop. The fluid flow 74 may comprise a fuel flow 108 (see FIG.15), a fuel vapor flow (not shown), inerting gasses (not shown), oranother suitable fluid. The vent dam 20 further comprises one or moreside flanges 50 (see FIG. 4 and FIG. 13A) extending from the contouredguiding surface 48 for providing attachment of the vent dam 20 to thevent stringer 28.

FIG. 5 is an illustration of a top view of a fuel vent system 52 in aleft aircraft wing box 54 with locations of the vent stringers 28 andembodiments of the vent dam 20 of the disclosure. An end 56 of the leftaircraft wing box 54 is attached to an aircraft fuselage 14 (see FIG.1). The fuel vent system 52 comprises vent stringers 28, non-ventstringers 58, and ribs 60. The vent stringers 28 may exist within one ormore fuel tanks 46, including a center wing tank 62, a main wing tank64, and a surge tank 66. The left aircraft wing box 54 may include oneor more fuel tanks 46, and the fuel tanks 46 may use one or more ventstringers 28 to move fluid flow 74 (see FIG. 9). The fuel tanks 46 maybe bound by ribs 60, spars 61, and wing skins (not shown). As can beseen in FIG. 5, the fuel vent system 52 has eight vent dams 20. However,the fuel vent system 52 may include more than eight vent dams or lessthan eight vent dams, depending on the type of aircraft used. Inaddition, the fuel vent system 52 may have the same number or adifferent number of vent dams 20 in the left wing as in the right wing.

FIG. 6 is an illustration of a top close-up view of the fuel vent system52 in the left aircraft wing box 54 with locations of vent stringers 28and embodiments of the vent dam 20 of the disclosure. FIG. 6 shows onlycertain vent stringers 28, non-vent stringers 58, and ribs 60, and alsoshows the center wing tank 62, the main wing tank 64, the surge tank 66,and a flammable leakage zone 68. Each vent dam 20 may be insertedthrough the opening 32 of the vent stringer 28 during installation. Inone embodiment, the opening 32 that the vent dam 20 may be insertedthrough may comprise an access opening 33 in the cap portion 30 (seeFIG. 14E) where the vent dam 20 is preferably positioned relative to oradjacent to the access opening 33 of the vent stringer 28.

In another embodiment as shown in FIG. 16F, the opening 32 that the ventdam 20 may be inserted through may comprise a base opening 35 betweenthe first web wall 40 and the second web wall 42. As shown in FIG. 9,one or more vent dams 20 may guide fluid flow 74 out of the ventstringer 28 into a tube 72. Preferably, the tube 72 is made of metal oranother suitable material. One or more vent dams 20 may prevent fluidflow 74 from flowing inboard 70 (see FIG. 6) and may guide the fluidflow 74 into the vent stringer 28. At other locations in the fuel ventsystem 52, vent dams 20 may guide fluid flow 74 inboard 70 or outboard71 (see FIG. 6) depending on system requirements. As shown in FIG. 6,one or more vent dams 20 may serve as a barrier 75 between the surgetank 66 and the flammable leakage zone 68 or at other tank boundarylocations in the fuel vent system 52.

FIG. 7 is an illustration of a top view of vent stringers 28 and anembodiment of the vent dam 20 of the disclosure, and also shows variousribs 60. FIG. 8 is an illustration of a close-up view of circled portion8 of FIG. 7 showing a top view of an embodiment of vent dams 20 near theopening 32 and near rib 60. The vent dams 20 may serve as the barrier 75between the surge tank 66 and the flammable leakage zone 68. FIG. 9 isan illustration of a close-up view of circled portion 9 of FIG. 7showing fluid flow 74 through a left main tank climb port 76. One ormore vent dams 20 may guide fluid flow 74 out of the tube 72 and intothe vent stringer 28. One or more vent dams 20 may prevent fluid flow 74from flowing inboard 70 and may guide the fluid flow 74 into the ventstringer 28. FIG. 10 is an illustration of a close-up view of circledportion 10 of FIG. 9 showing a perspective view of an embodiment of thevent dam 20 of the disclosure used to guide fluid flow 74 into the ventstringer 28 or out of the tube 72.

FIGS. 13A-FIG. 21E show various embodiments of the vent dam 20 disclosedherein for use in the fuel vent system 52. Preferably, the vent dam 20is fluid dynamic and is a fuel vent dam 172 (see, for example, FIG. 15)for use in the structural vent stringer 28 within the fuel tank 46. Thevent dam 20 comprises the contoured guiding surface 48 (see FIG. 4 andFIG. 13A) for guiding fluid flow 74 (see FIG. 9) into and out of thevent stringer 28. The vent dam 20 further comprises the one or more sideflanges 50 (see FIG. 4 and FIG. 13A) extending from the contouredguiding surface 48 for providing attachment of the vent dam 20 withinthe vent stringer 28. The contoured guiding surface 48 may be a curvedguiding surface 78 (see FIG. 12). FIG. 12 is an illustration of across-sectional view of an embodiment of the vent dam 20 of thedisclosure showing the curved guiding surface 78. The vent dam 20 isshown installed in the vent stringer 28 and relative to or adjacent tothe opening 32 of the vent stringer 28. The curved guiding surface 78may be tangent to the vent stringer 28 at points 80. However, the curvedguiding surface 78 does not require tangency to function effectively. Inanother embodiment, the contoured guiding surface 48 may be a slopedguiding surface 82 (see FIG. 11). FIG. 11 is an illustration of across-sectional view of an embodiment of the vent dam 20 of thedisclosure showing the sloped guiding surface 82. The vent dam 20 isshown installed in the vent stringer 28 and relative to or adjacent tothe opening 32 of the vent stringer 28. The sloped guiding surface 82may be sloped at an angle (not shown) in a range of from about 10degrees to about 170 degrees. Preferably, as shown in FIG. 11, thesloped guiding surface 82 is sloped at an angle 84 in a range of fromabout 30 degrees to about 60 degrees. The angle 84 shown is from point86 on the sloped guiding surface 82 to point 88 on a lower end 90 of theopening 32 of the vent stringer 28. Most preferably, the sloped guidingsurface 82 is sloped at an angle 92 of about 45 degrees.

The vent dam 20 may comprise a two piece vent dam 20A (shown in FIG.13A). The vent dam 20 may also comprise a one piece vent dam 20C (shownin FIG. 16A). The vent dam 20 may also comprise more than two pieces.The one or more side flanges 50 may be mechanically attached to the ventstringer 28 via one or more fastener elements 94 (see FIGS. 13E and13H). The fastener elements 94 may comprise a mechanical fastener 96,such as a threaded bolt 115 (see FIG. 13H). The fastener element 94 mayfurther comprise rivets (not shown) or another suitable fastenerelement. In another embodiment, the one or more side flanges 50 may bebonded or adhered to the vent stringer 28 via a bonding agent 98 (seeFIGS. 22-23). The bonding agent 98 may comprise an epoxy, an adhesive, asealant, or another suitable bonding agent. The vent dam 20 may be madeof a material comprising a composite material, such as a carbon fiberreinforcement plastic (CFRP), a carbon fiber impregnated fabric, nylon,a carbon fiber laminate, polyaryletheretherketone (PEEK), or anothersuitable composite material. Alternatively, the vent dam 20 may be madeof a metal material, such as aluminum, titanium, or another suitablemetal material. Preferably, the vent dam 20 is made of a material thatis compatible with a material that the vent stringer 28 is made ofand/or a material that the aircraft 10 is made of. For example, if thevent stringer 28 and aircraft 10 are made of a composite material, thevent dam 20 is preferably made of a composite material that iscompatible with the composite material of the vent stringer 28 and theaircraft 10. Similarly, if the vent stringer 28 and aircraft 10 are madeof a metal material, the vent dam 20 is preferably made of a metalmaterial that is compatible with the metal material of the vent stringer28 and the aircraft 10. Preferably, the one or more fastener elements 94may be in the form of mechanical fasteners 96, such as threaded bolts orrivets (not shown), for vent dams 20 made of a metal material.Alternatively, the vent dam 20 made of a metal material may be bonded inplace with the bonding agent 98. If the vent dam 20 is made of acomposite material, the one or more fastener elements 94 may be in theform of mechanical fasteners 96, such as threaded bolts or rivets (notshown), or the vent dam 20 may be bonded to the vent stringer 28 withthe bonding agent 98. Preferably, the embodiments of the vent dam 20disclosed herein are of a size and configuration that enable the ventdam 20 to be inserted and installed through the opening 32 in the ventstringer 28.

FIGS. 13A-13D are illustrations of views of an embodiment of the ventdam 20 in the form of a two piece vent dam 20A of the disclosure. FIG.13A is an illustration of a front perspective view of the two piece ventdam 20A. The two piece vent dam 20A is fluid dynamic and is preferablyfor use in the fuel vent system 52 (see FIG. 5) and in the fuel tank 46(see FIG. 5) of various aircraft. The two piece vent dam 20A comprises afirst piece 100 that can be joined to a second piece 102. FIG. 13A showsthe first piece 100 joined to the second piece 102 with an overlappingconfiguration 104 at a seam 106 formed between the first piece 100 andthe second piece 102. FIG. 13B is an illustration of the two piece ventdam 20A of FIG. 13A with the first piece 100 separated from the secondpiece 102. FIG. 13C is an illustration of a back view of the first piece100 of the two piece vent dam 20A of FIG. 13A. FIG. 13D is anillustration of a back view of the second piece 102 of the two piecevent dam 20A of FIG. 13A. The first piece 100 and the second piece 102of the two piece vent dam 20A each further comprise curved guidingsurface 78 for guiding fuel flow 108 (see FIG. 15) into and out of thevent stringer 28. The curved guiding surface 78 provides for smooth fuelflow 108 by preventing or minimizing turbulence which can result indecreased pressure drop.

The two piece vent dam 20A further comprises one or more side flanges 50extending from each curved guiding surface 78 for providing eithermechanical or bonding attachment of the two piece vent dam 20A to thevent stringer 28. The side flanges 50 may have one or more flange holes110 in which the one or more fastener elements 94 (see FIG. 13H) may beinserted to fasten and secure the two piece vent dam 20A to the ventstringer 28. As shown in FIG. 13F, the two piece vent dam 20A mayfurther comprise one or more attachment elements 112 for joining orattaching the first piece 100 to the second piece 102. The attachmentelement 112 may comprise a mechanical fastener 96 such as a threadedbolt 114 (see FIG. 13F). The attachment element 112 may further compriserivets or another suitable attachment element. The attachment element112 may be inserted through a hole 116 (FIG. 13B) in the first piece 100and through a slotted hole 118 (FIG. 13B) for tolerance in the secondpiece 102. The slotted hole 118 may have a cavity 120 having asufficient shape and depth to sink a head 121 of the threaded bolt 114and fair it in flush with the contoured guiding surface 48 of the twopiece vent dam 20A. The threaded bolt 114 may be grounded throughcontact with a threaded insert 124 shared between the two piece vent dam20A and the vent stringer 28. A grounding path 126 is shown with arrows.The threaded bolt 114 may be embedded in a portion 128 of the firstpiece 100.

FIG. 13E is an illustration a front perspective view of the two piecevent dam 20A of FIG. 13A installed in the vent stringer 28. FIG. 13Eshows the two piece vent dam 20A installed within the vent stringer 28and attached to both the vent stringer 28 and attached flange fitting 44with fastener elements 94. FIG. 13F is an illustration of across-sectional view of the vent dam 20A taken along line 13F-13F ofFIG. 13E showing the attachment element 112 in the form of threaded bolt114 for connecting the first piece 100 and the second piece 102 of thevent dam 20A. FIG. 13G is an illustration of a bottom view of the ventstringer 28 with the vent dam 20A of FIG. 13A installed in the ventstringer 28. FIG. 13H is an illustration of a cross-sectional view ofthe vent dam 20A taken along line 13H-13H of FIG. 13G showing themechanical fastener 94 in the form of threaded bolt 115 for connectingthe vent dam 20A to the vent stringer 28. As shown in FIG. 13G, theattach flange fitting 44 is attached over the vent stringer 28, and theopening 32 in the form of access opening 33 of the vent stringer 28shows the first piece 100 and the second piece 102 of the two piece ventdam 20A.

As shown in FIG. 13H, the mechanical fastener 94, in the form ofthreaded bolt 115, may be inserted through the hole 110 of the sideflange 50, and inserted and grounded through a sleeved interference fitfastener 132 shared with the vent stringer 28 and shared with the attachflange fitting 44. A collar 130 may be attached against an outer portion134 of the attach flange fitting 44 to secure the threaded bolt 115 inplace. The collar 130 may be fillet sealed. A fastener head 136 ispreferably interior to the vent stringer 28. If mechanically fastened, apotential ground path 138 may be provided through the mechanicalfastener 94. In this embodiment, the two piece vent dam 20A design ispreferably inserted through and fits through the opening 32 in the formof access opening 33 of the vent stringer 28 and allows for reliablesealing of each first piece 100 and second piece 102 to one or moreinterior portions 139 of the vent stringer 28 (see FIG. 13H). The twopiece vent dam 20A may be made of a suitable composite material, metalmaterial, or other suitable material.

FIGS. 14A-14D are illustrations of views of another embodiment of ventdam 20 in the form of a two piece vent dam 20B. FIG. 14A is anillustration of a front perspective view of the two piece vent dam 20B.The two piece vent dam 20B is preferably fluid dynamic and is preferablya fuel vent dam 172 for use in the vent stringer 28 within the fuel tank46 (see FIG. 15) of various aircraft. The two piece vent dam 20B issimilar to the two piece vent dam 20A, except the two piece vent dam 20Bdoes not have one or more attachment elements 112 for attaching thefirst piece 100 to the second piece 102. In addition, the two piece ventdam 20B has one or more end flanges 140 that may have one or more endflange holes 142 in which one or more fastener elements 94 (see FIG.14E) may be inserted to fasten and secure the end flanges 140 of the twopiece vent dam 20B to the vent stringer 28. The two piece vent dam 20Bcomprises first piece 100 that can be joined to second piece 102 viamechanical fasteners or bonding agents.

FIG. 14A shows the first piece 100 joined to the second piece 102 withthe overlapping configuration 104 at the seam 106 formed between thefirst piece 100 and the second piece 102. The first piece 100 may beattached to the second piece 102 via bonding using bonding agent 98,such as an epoxy, an adhesive, or another suitable bonding material.FIG. 14B is an illustration of the two piece vent dam 20B of FIG. 14Awith the first piece 100 separated from the second piece 102. The firstpiece 100 and the second piece 102 of the two piece vent dam 20B eachfurther comprise curved guiding surface 78 and one or more side flanges50 extending from each curved guiding surface 78. Each side flange 50may have one or more flange holes 110 in which one or more fastenerelements 94 (see FIG. 13H) may be inserted to fasten and secure the twopiece vent dam 20B to the vent stringer 28. FIG. 14C is an illustrationof a front view of the two piece vent dam 20B of FIG. 14A attached tothe vent stringer 28. FIG. 14D is an illustration of an outer side viewof the second piece 102 of the two piece vent dam 20B of FIG. 14Ashowing the curved guiding surface 78 and the bend radius 79. FIG. 14Eis an illustration of a front perspective view of the two piece vent dam20B of FIG. 14A installed in the vent stringer 28. The two piece ventdam 20B may be inserted through the opening 32 in the form of accessopening 33 on the cap portion 30 of the vent stringer 28 and attachedwithin the vent stringer 28. The two piece vent dam 20B is preferablyattached so that it is flush against interior portions 139 of the ventstringer 28. As shown in FIG. 14E, the vent stringer 28 is preferablyadjacent to an upper wing skin 141. FIG. 14F is an illustration of abottom perspective view of the two piece vent dam 20B of FIG. 14Ainstalled in the vent stringer 28. The two piece vent dam 20B may bemade of a suitable composite material, a suitable metal material, oranother suitable material. FIG. 14G is an illustration of a perspectiveview of the vent dam 20B of FIG. 14A without any side flange holes 110and without any end flange holes 142, which is a preferred configurationif the vent dam 20B is bonded to the vent stringer 28 rather thanmechanically fastened.

FIG. 15 is an illustration of a cut-away side view of the vent dam 20 inthe form of the two piece vent dam 20B installed in the vent stringer 28within the fuel tank 46. The vent dam 20, in the form of two piece ventdam 20B, comprises the first piece 100 joined to the second piece 102with the overlapping configuration 104 at the seam 106 (see also FIG.14A) formed between the first piece 100 and the second piece 102.Preferably, the vent dam 20 is a fuel vent dam 172 comprising thecontoured guiding surface 48 in the form of the curved guiding surface78. Preferably, the vent dam 20 further comprises one or more sideflanges 50 extending from the contoured guiding surface 48. The one ormore side flanges 50 of the vent dam 20 are preferably attached to oneor more interior portions 139 of the vent stringer 28 of the fuel tank46. The vent dam 20, in the form of the fuel vent dam 172, is preferablyinstalled adjacent to the opening 32, in the form of access opening 33,in the vent stringer 28.

FIG. 15 shows fuel flow 108 (as indicated with arrows) entering fromtube 72 attached to the vent stringer 28 and entering through theopening 32 into an interior 143 of the vent stringer 28. The contouredguiding surface 48 of the vent dam 20 guides the fuel flow 108 thatenters or is introduced through the opening 32 and directs the fuel flow108 down a vent stringer channel 144. The contoured guiding surface 48guides the fuel flow 108 into and out of the vent stringer 28. Thecontoured guiding surface 48, in the form of the curved guiding surface78, is preferably designed to smoothly expand or funnel the fuel flow108 away from the opening 32, in the form of access opening 33.Alternatively, the contoured guiding surface 48 may guide the fuel flow108 towards the opening 32. The contoured guiding surface 48 preferablyprevents turbulence (not shown) in the fuel flow 108, which results in areduced pressure drop 77 (see FIG. 15 (↓P)) across the vent dam 20B toimprove fuel flow in the vent stringer 28 in the fuel tank 46. Improvedfuel flow may include increased speed of the fuel flow through the fueltank and the fuel vent system and increased efficiency of the fuel flowthrough the fuel tank and the fuel vent system. The resistancecoefficient (K) for fuel flow 108 past the vent dam 20B is preferablyimproved over the value assigned to a known 90° (degree) miter bend. Abend radius 79 on the contoured guiding surface 48, in the form of thecurved guiding surface 78, can facilitate the reduced pressure drop 77and improved fuel flow. Because the resistance coefficient (K) is afunction of the bend radius 79 of the vent dam 20, the performance ofthe vent dam 20 can be optimized by maximizing the bend radius 79 of thecontoured guiding surface 48 within the vent stringer channel 144.Generally, as long as the fuel flow is not impeded, the larger the bendradius of the contoured guiding surface, the lower the pressure dropacross the vent dam. Given that one or more vent dams 20 may be utilizedin the fuel tanks 46 throughout the fuel vent system 52 (see FIG. 5),and the reduced pressure drop is additive, increased fuel flow speed andefficiency can be realized.

FIGS. 16A-16D are illustrations of views of another embodiment of ventdam 20 in the form of a one piece vent dam 20C. FIG. 16A is anillustration of a perspective view of the one piece vent dam 20C. FIG.16B is an illustration of a front view of the one piece vent dam 20C ofFIG. 16A. FIG. 16C is an illustration of a back view of the one piecevent dam 20C of FIG. 16A. FIG. 16D is an illustration of a side view ofthe one piece vent dam 20C of FIG. 16A. The one piece vent dam 20Ccomprises contoured guiding surface 48 shown in the form of curvedguiding surface 78 with bend radius 79 and one or more side flanges 50extending from the curved guiding surface 78. Each side flange 50 mayhave one or more flange holes 110 in which one or more fastener elements94 (see FIG. 13H) may be inserted to fasten and secure the two piecevent dam 20C to the vent stringer 28. The one piece vent dam 20C furthercomprises end flange 140 having one or more flange holes 142 in whichone or more fastener elements 94 (see FIG. 13H) may be inserted tofasten and secure the end flange 140 of the two piece vent dam 20C tothe vent stringer 28. FIG. 16E is an illustration of a cut-away frontview of the one piece vent dam 20C of FIG. 16A installed in the ventstringer 28. The one piece vent dam 20C is preferably mated to the upperwing skin 141 as closely as possible. FIG. 16F is an illustration of abottom perspective view of the one piece vent dam 20C of FIG. 16Ainstalled in the vent stringer 28. FIG. 16G is an illustration of abottom view of the one piece vent dam 20C of FIG.16A installed in thevent stringer 28. FIG. 16H is an illustration of a top view of the onepiece vent dam 20C of FIG. 16A installed in the vent stringer 28. Theone piece vent dam 20C may be made of a suitable metal material, asuitable composite material, or another suitable material. FIG. 16I isan illustration of a perspective view of the vent dam 20C of FIG. 16Awithout any side flange holes 110 and without any end flange holes 142,which is a preferred configuration if the vent dam 20C is bonded to thevent stringer 28 rather than mechanically fastened.

FIG. 17 is an illustration of a cut-away side view of the vent dam 20 inthe form of the one piece vent dam 20C of FIG. 16A installed in the ventstringer 28 and showing fluid flow 74. FIG. 17 shows the one piece ventdam 20C installed within the vent stringer 28. The vent dam 20, in theform of one piece vent dam 20C, comprises the contoured guiding surface48 in the form of the curved guiding surface 78, and further comprisesone or more side flanges 50 extending from the contoured guiding surface48. The one or more side flanges 50 of the of the vent dam 20 arepreferably attached to one or more interior portions 139 of the ventstringer 28 of the fuel vent system 52. The vent dam 20 is preferablyinstalled adjacent to or relative to the opening 32, in the form ofaccess opening 33, in the vent stringer 28.

FIG. 17 shows fluid flow 74 (as indicated with arrows) through theopening 32 into interior 143 of the vent stringer 28. The contouredguiding surface 48 of the vent dam 20, in the form of one piece vent dam20C, guides the fluid flow 74 that enters or is introduced through theopening 32 and directs the fluid flow 74 down the vent stringer channel144. The contoured guiding surface 48 guides the fluid flow 74 into andout of the vent stringer 28. The contoured guiding surface 48, in theform of the curved guiding surface 78, is preferably designed tosmoothly expand or funnel the fluid flow 74 away from the opening 32, inthe form of access opening 33. Alternatively, the contoured guidingsurface 48 may guide the fluid flow 74 towards the opening 32. Thecontoured guiding surface 48 preferably prevents turbulence (not shown)in the fluid flow 74, which results in a reduced pressure drop 77 acrossthe vent dam 20C to improve fluid flow in the vent stringer 28 of thefuel vent system 52. Improved fluid flow may include increased speed ofthe fluid flow through the fuel vent system and increased efficiency ofthe fluid flow through the fuel vent system. The resistance coefficient(K) for fluid flow 74 past the vent dam 20C may be improved over thevalue assigned to a known 90° (degree) miter bend. A bend radius 79 onthe contoured guiding surface 48, in the form of the curved guidingsurface 78, can facilitate the reduced pressure drop 77 and improvedfluid flow. Because the resistance coefficient (K) is a function of thebend radius 79 of the vent dam 20, the performance of the vent dam 20can be optimized by maximizing the bend radius 79 of the contouredguiding surface 48 within the vent stringer channel 144. Generally, aslong as the fluid flow is not impeded, the larger the bend radius of thecontoured guiding surface, the lower the pressure drop across the ventdam. Given that one or more vent dams 20 may be utilized throughout thefuel vent system 52 (see FIG. 5), and the reduced pressure drop isadditive, increased fluid flow speed and efficiency can be realized.

FIGS. 18-A-18D are illustrations of views of another embodiment of ventdam 20 in the form of a two piece vent dam 20D having attachment element112. The attachment element 112 is shown in the form of a maleprojecting portion 150 on the second piece 102 and a correspondingfemale slot portion 152 on the first piece 100 to connect the firstpiece 100 and the second piece 102 together. FIG. 18A is an illustrationof a front perspective view of the two piece vent dam 20D. The two piecevent dam 20D comprises first piece 100 that may be joined to secondpiece 102 with the overlapping configuration 104 at the seam 106. Thefirst piece 100 and the second piece 102 of the two piece vent dam 20Deach further comprise curved guiding surface 78 and one or more sideflanges 50 extending from each edge 154 of the curved guiding surface78. Each side flange 50 may have one or more flange holes 110 in whichone or more fastener elements 94 (see FIG. 13H) may be inserted tofasten and secure the two piece vent dam 20D to the vent stringer 28.The first piece 100 and the second piece 102 of the two piece vent dam20D may each further comprise one or more end flanges 140 having one ormore end flange holes 142 in which one or more fastener elements 94 (seeFIG. 14E) may be inserted to fasten and secure the end flanges 140 tothe vent stringer 28. Alternatively, the side flanges 50 and the endflanges 140 may be bonded to the vent stringer 28 with a bonding agent98 rather than mechanically fastened. FIG. 18B is an illustration of thetwo piece vent dam 20D with the first piece 100 separated from thesecond piece 102. The first piece 100 may be securely attached to thesecond piece 102 by inserting the male projection portion 152 on thefirst piece 100 into the female slot portion 152 on the second piece102. FIG. 18C is an illustration of a side view of the first piece 100of the two piece vent dam 20D of FIG. 18A. FIG. 18C shows the curvedguiding surface 78 with bend radius 79. FIG. 18D is an illustration of aback view of the second piece 102 of the two piece vent dam 20D of FIG.18A. The two piece vent dam 20D may be made of a suitable compositematerial or another suitable material.

FIGS. 19A-19C are illustrations of views of another embodiment of ventdam 20 in the form of a two piece vent dam 20E having attachment element112. The attachment element 112 is shown in the form of a first set ofinterlocking fingers 158 formed on the first piece 100 and a second setof interlocking fingers 160 formed on the second piece 102. The firstset of interlocking fingers 158 interconnect with the second set ofinterlocking fingers 160 to securely join or connect the first piece 100and the second piece 102 together. FIG. 19A is an illustration of afront view of the two piece vent dam 20E installed in the vent stringer28. FIG. 19B is an illustration of a top view of the two piece vent dam20E through the access opening 33 of the vent stringer 28. FIG. 19C isan illustration of a side view of the two piece vent dam 20E. The firstpiece 100 and the second piece 102 of the two piece vent dam 20E eachcomprise curved guiding surface 78 with bend radius 79 and one or moreside flanges 50 extending from each curved guiding surface 78. Each sideflange 50 may have one or more flange holes 110 in which one or morefastener elements 94 (see FIG. 13H) may be inserted to fasten and securethe two piece vent dam 20E to the vent stringer 28. The first piece 100and the second piece 102 of the two piece vent dam 20E may each furthercomprise one or more end flanges 140 having one or more end flange holes142 in which one or more fastener elements (see FIG. 14E) may beinserted to fasten and secure the end flanges 140 to the vent stringer28. Alternatively, the side flanges 50 and the end flanges 140 may bebonded to the vent stringer 28 with a bonding agent 98 rather thanmechanically fastened. The two piece vent dam 20E may be made of asuitable composite material or another suitable material.

FIGS. 20A-20C are illustrations of views of another embodiment of ventdam 20 in the form of a two piece vent dam 20F having attachment element112. The attachment element 112 is shown in the form of a pin 162inserted through the first web wall 40 of the vent stringer 28 tosecurely join or connect the first piece 100 and the second piece 102together. Alternatively, the pin 162 may be inserted through the secondweb wall 42 or through both the first web wall 40 and the second webwall 42. FIG. 20A is an illustration of a back view of the two piecevent dam 20F installed in the vent stringer 28. FIG. 20A shows the pin162 entering through an opening 164 in the first web wall 40 and goingthrough the first piece 100 and the second piece 102. FIG. 20B is anillustration of a top view of the two piece vent dam 20F through theaccess opening 33 of the vent stringer 28. FIG. 20C is an illustrationof a side view of the two piece vent dam 20F. The first piece 100 andthe second piece 102 of the two piece vent dam 20F each comprise thecurved guiding surface 78 with bend radius 79 and one or more sideflanges 50 extending from each curved guiding surface 78. Each sideflange 50 may have one or more flange holes 110 in which one or morefastener elements 94 (see FIG. 13H) may be inserted to fasten and securethe two piece vent dam 20F to the vent stringer 28. The first piece 100and the second piece 102 of the two piece vent dam 20F may each furthercomprise one or more end flanges 140 having one or more end flange holes142 in which one or more fastener elements 94 (see FIG. 14E) may beinserted to fasten and secure the end flanges 140 to the vent stringer28. Alternatively, the side flanges 50 and the end flanges 140 may bebonded to the vent stringer 28 with a bonding agent 98 rather thanmechanically fastened. The two piece vent dam 20F may be made of asuitable composite material, a suitable metal material, or anothersuitable material.

FIGS. 21A-21D are illustrations of views of another embodiment of ventdam 20 in the form of a two piece vent dam 20G having the sloped guidingsurface 82 rather than the curved guiding surface 78. FIG. 21A is anillustration of a front perspective view of the two piece vent dam 20G.The two piece vent dam 20G comprises first piece 100 that may be joinedto second piece 102 with the overlapping configuration 104 at the seam106. The first piece 100 and the second piece 102 of the two piece ventdam 20G each further comprise the sloped guiding surface 82 and one ormore side flanges 50 extending from each sloped guiding surface 82. Eachside flange 50 may have one or more flange holes 110 in which one ormore fastener elements 94 (see FIG. 13H) may be inserted to fasten andsecure the two piece vent dam 20G to the vent stringer 28. The firstpiece 100 and the second piece 102 of the two piece vent dam 20G mayeach further comprise one or more end flanges 140 on both ends 166. FIG.21B is an illustration of a top view of the two piece vent dam 20G. FIG.21C is an illustration of a back view of the two piece vent dam 20G.FIG. 21D is an illustration of a side view of the first piece 100 of thetwo piece vent dam 20G of FIG. 21A. FIG. 21E is an illustration of aperspective view of the vent dam 20G of FIG. 21A without any side flangeholes 110, which is a preferred configuration if the vent dam 20G isbonded to the vent stringer 28 rather than mechanically fastened. Thetwo piece vent dam 20G may be made of a suitable composite material oranother suitable material.

FIG. 22 is an illustration of a front perspective view of an embodimentof vent dam 20 of the disclosure installed in the vent stringer 28 withthe bonding agent 98. FIG. 23 is an illustration of a bottom view of thevent dam 20 of FIG. 22 showing the vent dam 20 installed in the ventstringer 28 with the bonding agent 98.

FIG. 24 is an illustration of a flow diagram of an embodiment of amethod 300 of the disclosure for providing improved fluid flow 74 in afuel vent system 52 (see FIG. 17). The method 300 comprises step 302 ofproviding a vent dam 20, which for example, may be in the form of any ofthe vent dams 20A-20G (see FIGS. 13A-21E). The vent dam 20 may comprisea two piece vent dam 20A (FIG. 13A), 20B (FIG. 14A), 20D (FIG. 18A), 20E(FIG. 19A), 20F (FIG. 20A), and 20G (FIG. 21A). The vent dam 20 may alsocomprise a one piece vent dam 20C (see FIG. 16A). The vent dam 20comprises a contoured guiding surface 48 and one or more side flanges 50extending from the contoured guiding surface 48. The vent dam 20comprises the contoured guiding surface 48, in the form of the curvedguiding surface 78, and further comprises one or more side flanges 50extending from the contoured guiding surface 48. In one of theembodiments as shown in FIG. 17, the contoured guiding surface 48 may bein the form of the curved guiding surface 78 and have a bend radius 79.In another of the embodiments as shown in FIG. 11, the contoured guidingsurface 48 may be in the form of a sloped guiding surface 82 sloped atan angle 84 in a range of from about 30 degrees to about 60 degrees.

The method 300 further comprises step 304 of installing the vent dam 20in a vent stringer 28 adjacent to an opening 32 in the vent stringer 28.In an exemplary embodiment as shown in FIG. 17, the vent dam 20C isinstalled within the vent stringer 28. The one or more side flanges 50of the vent dam 20C are preferably attached to one or more interiorportions 139 of the vent stringer 28 of the fuel vent system 52. In oneof the embodiments, the one or more side flanges 50 may be mechanicallyattached to the vent stringer 28 via one or more fastener elements 94(see FIG. 13H). In another one of the embodiments, the one or more sideflanges 50 may be bonded to the vent stringer 28 with a bonding agent 98(see FIGS. 22-23). The vent dam 20C is preferably installed adjacent toor relative to the opening 32, in the form of access opening 33, in thevent stringer 28. In one of the embodiments, the opening 32 that thevent dam 20 may be inserted through may comprise an access opening 33 inthe cap portion 30 (see FIG. 14E) where the vent dam 20 is preferablypositioned relative to or adjacent to the access opening 33 of the ventstringer 28. In another one of the embodiments, the opening 32 that thevent dam 20 may be inserted through may comprise a base opening 35between the first web wall 40 and the second web wall 42 (see FIG. 16F).

The method 300 further comprises step 306 of introducing a fluid flow 74(see FIG. 17) through the opening 32 in the vent stringer 28. FIG. 17shows fluid flow 74 (as indicated with arrows) entering or beingintroduced through the opening 32 into interior 143 of the vent stringer28. The method 300 further comprises step 308 of using the contouredguiding surface 48 to guide the fluid flow 74 into and out of the ventstringer 28. As shown in FIG. 17, the contoured guiding surface 48 ofthe vent dam 20C guides the fluid flow 74 that enters or is introducedthrough the opening 32 and directs the fluid flow 74 down the ventstringer channel 144. The contoured guiding surface 48 guides the fluidflow 74 into and out of the vent stringer 28. The contoured guidingsurface 48 is designed to smoothly expand or funnel the fluid flow 74past the vent dam 20 and preferably away from the opening 32.Alternatively, the contoured guiding surface 48 may guide the fluid flow74 towards the opening 32.

The method 300 further comprises step 310 of using the contoured guidingsurface 48 to prevent turbulence (not shown) in the fluid flow 74 whichresults in a reduced pressure drop 77 (see FIG. 17 (↓P)) across the ventdam 20 to improve fluid flow in the vent stringer 28 of the fuel ventsystem 52. Improved fluid flow may include increased speed of the fluidflow through the fuel vent system and increased efficiency of the fluidflow through the fuel vent system. The bend radius 79 (see FIG. 17) onthe contoured guiding surface 48, in the form of the curved guidingsurface 78, can facilitate the reduced pressure drop 77 and improvedfluid flow. Because the resistance coefficient (K) is a function of thebend radius 79 of the vent dam 20, the performance of the vent dam 20can be optimized by maximizing the bend radius 79 of the contouredguiding surface 48 within the vent stringer channel 144. Preferably, thelarger the bend radius 79 of the contoured guiding surface 48, the lowerthe pressure drop 77 across the vent dam 20. Given that one or more ventdams 20 may be utilized throughout the fuel vent system 52 (see FIG. 5),and the reduced pressure drop is additive, increased fluid flow speedand efficiency can be realized.

FIG. 25 is an illustration of a flow diagram of another embodiment of amethod 400 of the disclosure for providing improved fuel flow 108 in avent stringer 28 in a fuel tank 46 (see FIG. 15). The method 400comprises step 402 of providing a vent dam 20, which for example, maypreferably comprise a two piece vent dam 20A (FIG. 13A), 20B (FIG. 14A),20D (FIG. 18A), 20E (FIG. 19A), 20F (FIG. 20A), or 20G (FIG. 21A). Asshown in FIG. 15, the vent dam 20 comprises a first piece 100 joined toa second piece 102 with an overlapping configuration 104 at a seam 106formed between the first piece 100 and the second piece 102. The ventdam 20 further comprises a contoured guiding surface 48 and one or moreside flanges 50 extending from the contoured guiding surface 48.Preferably, the vent dam 20 is a fuel vent dam 172 (see FIG. 15). In oneof the embodiments as shown in FIG. 15, the contoured guiding surface 48may be in the form of the curved guiding surface 78 and have a bendradius 79. In another of the embodiments as shown in FIG. 11, thecontoured guiding surface 48 may be in the form of a sloped guidingsurface 82 sloped at an angle 84 in a range of from about 30 degrees toabout 60 degrees.

The method 400 further comprises step 404 of attaching the one or moreside flanges 50 of the vent dam 20 to one or more interior portions 139of the vent stringer 28 in the fuel tank 46. Preferably, the vent dam20, in the form of the fuel vent dam 172, is installed adjacent to orrelative to the opening 32, in the form of access opening 33, in thevent stringer 28. In an exemplary embodiment as shown in FIG. 15, thevent dam 20B is installed within the vent stringer 28. The one or moreside flanges 50 of the vent dam 20B are preferably attached to one ormore interior portions 139 of the vent stringer 28 of the fuel tank 46.In one of the embodiments, the one or more side flanges 50 may bemechanically attached to the vent stringer 28 via one or more fastenerelements 94 (see FIG. 13H). In another one of the embodiments, the oneor more side flanges 50 may be bonded to the vent stringer 28 with abonding agent 98 (see FIGS. 22-23). The vent dam 20B is preferablyinstalled adjacent to or relative to the opening 32, in the form ofaccess opening 33, in the vent stringer 28. In one of the embodiments,the opening 32 that the vent dam 20 may be inserted through may comprisean access opening 33 in the cap portion 30 (see FIG. 14E) where the ventdam 20 is preferably positioned relative to or adjacent to the accessopening 33 of the vent stringer 28. In another one of the embodiments,the opening 32 that the vent dam 20 may be inserted through may comprisea base opening 35 between the first web wall 40 and the second web wall42 (see FIG. 16F).

The method 400 further comprises step 406 of introducing a fuel flow 108(see FIG. 15) through the opening 32 in the vent stringer 28. FIG. 15shows fuel flow 108 (as indicated with arrows) entering from tube 72attached to the vent stringer 28 and entering through the opening 32into an interior 143 of the vent stringer 28.

The method 400 further comprises step 408 of using the contoured guidingsurface 48 to guide the fuel flow 108 into and out of the vent stringer28. As shown in FIG. 15, the contoured guiding surface 48 of the ventdam 20 guides the fuel flow 108 that enters or is introduced through theopening 32 and directs the fuel flow 108 down the vent stringer channel144. The contoured guiding surface 48 guides the fuel flow 108 into andout of the vent stringer 28. The contoured guiding surface 48 isdesigned to smoothly expand or funnel the fuel flow 108 past the ventdam 20 and preferably away from the opening 32. Alternatively, thecontoured guiding surface 48 may guide the fuel flow 108 towards theopening 32.

The method 400 further comprises step 410 of using the contoured guidingsurface 48 to prevent turbulence (not shown) in the fuel flow 108 whichresults in a reduced pressure drop 77 (see FIG. 15 (↓P)) across the ventdam 20 to improve fuel flow in the vent stringer 28 in the fuel tank 46.Improved fuel flow may include increased speed of the fuel flow throughthe fuel tank and fuel vent system and increased efficiency of the fuelflow through the fuel tank and fuel vent system. The bend radius 79 (seeFIG. 15) on the contoured guiding surface 48, in the form of the curvedguiding surface 78, can facilitate the reduced pressure drop 77 andimproved fluid flow. Because the resistance coefficient (K) is afunction of the bend radius 79 of the vent dam 20, the performance ofthe vent dam 20 can be optimized by maximizing the bend radius 79 of thecontoured guiding surface 48 within the vent stringer channel 144.Preferably, the larger the bend radius 79 of the contoured guidingsurface 48, the lower the pressure drop 77 across the vent dam 20. Giventhat one or more vent dams 20 may be utilized in the fuel tanks 46throughout the fuel vent system 52 (see FIG. 5), and the reducedpressure drop is additive, increased fuel flow speed and efficiency canbe realized.

Many modifications and other embodiments of the disclosure will come tomind to one skilled in the art to which this disclosure pertains havingthe benefit of the teachings presented in the foregoing descriptions andthe associated drawings. The embodiments described herein are meant tobe illustrative and are not intended to be limiting or exhaustive.Although specific terms are employed herein, they are used in a genericand descriptive sense only and not for purposes of limitation.

What is claimed is:
 1. A vent dam for use in a vent stringer in a fuelvent system, the vent dam configured to mount to and within the ventstringer, the vent dam comprising: a contoured guiding surface forguiding fuel flow into and out of an interior of the vent stringer,wherein the vent dam, the vent stringer, and a tube attached to the ventstringer are in fluid communication with one or more fuel tanks; and,one or more side flanges extending from the contoured guiding surfacefor providing attachment of the vent dam to one or more interiorportions of the vent stringer, wherein the contoured guiding surface andthe one or more side flanges are formed as one piece.
 2. The vent dam ofclaim 1, wherein the contoured guiding surface is curved.
 3. The ventdam of claim 1, wherein the contoured guiding surface is sloped at anangle in a range of from about 30 degrees to about 60 degrees.
 4. Thevent dam of claim 1, wherein the contoured guiding surface is sloped atan angle of about 45 degrees.
 5. The vent dam of claim 1, wherein theone or more side flanges are mechanically attached to the vent stringervia one or more fastener elements.
 6. The vent dam of claim 1, whereinthe one or more side flanges are bonded to the vent stringer via abonding agent.
 7. The vent dam of claim 1, further comprising an endflange having one or more flange holes in which one or more fastenerelements are inserted to fasten and secure the end flange of the ventdam to the vent stringer.
 8. The vent dam of claim 1, wherein the ventdam is made of a material selected from the group comprising a compositematerial, a metal material, aluminum, titanium, carbon fiberreinforcement plastic (CFRP), a carbon fiber impregnated fabric, nylon,carbon fiber laminate, and polyaryletheretherketone (PEEK).
 9. The ventdam of claim 1, wherein the vent dam is made of a material that iscompatible with a material comprising the vent stringer.
 10. An aircraftstructure comprising: at least one wing; at least one vent stringermounted to the at least one wing, the at least one vent stringercomprising a base portion, first and second web walls extendingoutwardly from the base portion, a cap portion, and an access opening inthe cap portion, the access opening configured for insertion andinstallation of vent dams; at least one fuel tank; and, the vent damsmounted to and within the at least one vent stringer, the vent dams eachcomprising: a contoured guiding surface for guiding fuel flow into andout of an interior of the at least one vent stringer, wherein the ventdams, the at least one vent stringer, and a tube attached to the atleast one vent stringer are in fluid communication with the at least onefuel tank; and, one or more side flanges extending from the contouredguiding surface for providing attachment of the vent dams to one or moreinterior portions of the at least one vent stringer, wherein at leastone of the vent dams is formed as one piece.
 11. The aircraft structureof claim 10, wherein the contoured guiding surface is curved.
 12. Theaircraft structure of claim 10, wherein the contoured guiding surface issloped at an angle in a range of from about 30 degrees to about 60degrees.
 13. The aircraft structure of claim 10, wherein the vent damseach further comprise an end flange having one or more flange holes inwhich one or more fastener elements is inserted to fasten and secure theend flange of the vent dam to the vent stringer.
 14. The aircraftstructure of claim 10, wherein the one or more side flanges aremechanically attached to the vent stringer via one or more fastenerelements.
 15. The aircraft structure of claim 10, wherein the one ormore side flanges are bonded to the vent stringer via a bonding agent.16. A method for providing improved fluid flow in a vent stringer of afuel vent system, the method comprising: attaching one or more sideflanges of a vent dam to one or more interior portions of the ventstringer in a fuel tank, the vent dam being adjacent to an opening inthe vent stringer, wherein the vent dam includes a contoured guidingsurface and the one or more side flanges extending from the contouredguiding surface, and wherein the contoured guiding surface and the oneor more side flanges are formed as one piece.
 17. The method of claim16, further comprising: introducing a fluid flow through the opening inthe vent stringer; using the contoured guiding surface to guide thefluid flow into and out of the vent stringer, wherein the vent dam, thevent stringer, and a tube attached to the vent stringer are in fluidcommunication with the fuel tank; and, using the contoured guidingsurface to prevent turbulence in the fluid flow which results in areduced pressure drop across the vent dam to improve fluid flow in thevent stringer of the fuel vent system.
 18. The method of claim 16,wherein the attaching the one or more side flanges of the vent damcomprises attaching the vent dam with the contoured guiding surfacebeing curved and having a bend radius.
 19. The method of claim 16,wherein the attaching the one or more side flanges of the vent damcomprises inserting one or more fastener elements through one or moreflange holes defined through an end flange of the vent dam to fasten andsecure the end flange of the vent dam to the vent stringer in the fueltank.
 20. The method of claim 16, wherein the attaching the one or moreside flanges of the vent dam comprises mechanically attaching the one ormore side flanges to the vent stringer via one or more fastenerelements.
 21. The method of claim 16, wherein the attaching the one ormore side flanges of the vent dam comprises bonding the one or more sideflanges to the vent stringer via a bonding agent.